import 'dart:io';
import 'package:camera/camera.dart' as camera_pkg;
import 'package:sino_med_cloud/core/utils/logger.dart';
import 'media_exception.dart';

// 使用别名避免命名冲突
typedef CameraController = camera_pkg.CameraController;
typedef ResolutionPreset = camera_pkg.ResolutionPreset;
typedef CameraLensDirection = camera_pkg.CameraLensDirection;
typedef XFile = camera_pkg.XFile;

/// 专业相机服务
/// 
/// 适合医疗影像、证件采集、高质量拍照、连拍/自定义UI
/// 
/// 使用示例：
/// ```dart
/// final cameraService = CameraService();
/// await cameraService.init();
/// final photo = await cameraService.takePicture();
/// cameraService.dispose();
/// ```
class CameraService {
  CameraController? _controller;
  bool _isInitialized = false;
  bool _isDisposed = false;

  /// 初始化相机
  /// 
  /// - [resolutionPreset] 分辨率预设，默认 veryHigh
  /// - [enableAudio] 是否启用音频，默认 false
  /// - [lensDirection] 镜头方向，默认后置摄像头
  /// 
  /// 抛出 [MediaCameraException] 如果初始化失败
  Future<void> init({
    ResolutionPreset resolutionPreset = camera_pkg.ResolutionPreset.veryHigh,
    bool enableAudio = false,
    CameraLensDirection lensDirection = camera_pkg.CameraLensDirection.back,
  }) async {
    try {
      if (_isDisposed) {
        throw MediaCameraException('相机服务已释放，无法初始化');
      }

      if (_isInitialized) {
        AppLogger.d('相机已初始化，跳过重复初始化');
        return;
      }

      AppLogger.d('开始初始化相机...');
      final cameras = await camera_pkg.availableCameras();
      
      if (cameras.isEmpty) {
        throw MediaCameraException('未找到可用相机');
      }

      final camera = cameras.firstWhere(
        (c) => c.lensDirection == lensDirection,
        orElse: () => cameras.first,
      );

      _controller = camera_pkg.CameraController(
        camera,
        resolutionPreset,
        enableAudio: enableAudio,
      );

      await _controller!.initialize();
      _isInitialized = true;
      AppLogger.d('相机初始化成功: ${camera.name}');
    } catch (e) {
      _isInitialized = false;
      if (e is camera_pkg.CameraException) {
        AppLogger.e('相机初始化失败（原生异常）', e);
        throw MediaCameraException(
          '相机初始化失败: ${e.toString()}',
          originalError: e,
        );
      }
      if (e is MediaCameraException) {
        rethrow;
      }
      AppLogger.e('相机初始化失败', e);
      throw MediaCameraException(
        '相机初始化失败: ${e.toString()}',
        originalError: e,
      );
    }
  }

  /// 获取相机控制器
  /// 
  /// 抛出 [MediaCameraException] 如果相机未初始化
  CameraController get controller {
    if (!_isInitialized || _controller == null) {
      throw MediaCameraException('相机未初始化，请先调用 init()');
    }
    return _controller!;
  }

  /// 检查相机是否已初始化
  bool get isInitialized => _isInitialized && _controller?.value.isInitialized == true;

  /// 拍照
  /// 
  /// 返回拍摄的照片文件，如果失败返回 null
  /// 
  /// 抛出 [MediaCameraException] 如果拍照失败
  Future<File?> takePicture() async {
    try {
      if (!isInitialized) {
        throw MediaCameraException('相机未初始化，无法拍照');
      }

      AppLogger.d('开始拍照...');
      final camera_pkg.XFile file = await _controller!.takePicture();
      final photoFile = File(file.path);

      if (!await photoFile.exists()) {
        throw MediaCameraException('拍照失败：文件不存在');
      }

      AppLogger.d('拍照成功: ${photoFile.path}');
      return photoFile;
    } catch (e) {
      if (e is camera_pkg.CameraException) {
        AppLogger.e('拍照失败（原生异常）', e);
        throw MediaCameraException(
          '拍照失败: ${e.toString()}',
          originalError: e,
        );
      }
      if (e is MediaCameraException) {
        rethrow;
      }
      AppLogger.e('拍照失败', e);
      throw MediaCameraException(
        '拍照失败: ${e.toString()}',
        originalError: e,
      );
    }
  }

  /// 释放相机资源
  /// 
  /// 必须在不再使用相机时调用，否则可能导致资源泄漏
  Future<void> dispose() async {
    if (_isDisposed) {
      return;
    }

    try {
      if (_controller != null) {
        await _controller!.dispose();
        _controller = null;
      }
      _isInitialized = false;
      _isDisposed = true;
      AppLogger.d('相机资源已释放');
    } catch (e) {
      AppLogger.e('释放相机资源失败', e);
    }
  }
}